吸光光度法（紫外/可见光谱）讲座（7）
<H2 style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 150%; TEXT-ALIGN: center; mso-layout-grid-align: none" align=center><SPAN style="FONT-SIZE: 14pt; FONT-FAMILY: 黑体; mso-bidi-font-size: 16.0pt; mso-ascii-font-family: Arial; mso-font-kerning: 0pt">吸光光度法（紫外</SPAN><SPAN lang=EN-US style="FONT-SIZE: 14pt; mso-bidi-font-size: 16.0pt; mso-font-kerning: 0pt"><FONT face=Arial>/</FONT></SPAN><SPAN style="FONT-SIZE: 14pt; FONT-FAMILY: 黑体; mso-bidi-font-size: 16.0pt; mso-ascii-font-family: Arial; mso-font-kerning: 0pt">可见光谱）讲座（</SPAN><SPAN lang=EN-US style="FONT-SIZE: 14pt; mso-bidi-font-size: 16.0pt; mso-font-kerning: 0pt"><FONT face=Arial>7</FONT></SPAN><SPAN style="FONT-SIZE: 14pt; FONT-FAMILY: 黑体; mso-bidi-font-size: 16.0pt; mso-ascii-font-family: Arial; mso-font-kerning: 0pt">）<FONT face=Arial><BR></FONT></SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-bidi-font-size: 16.0pt; mso-font-kerning: 0pt">――</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 16.0pt; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">应用吸光光度法测定配合物的组成</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-bidi-font-size: 16.0pt; mso-font-kerning: 0pt"><?xml:namespace prefix = o /><o:p></o:p></SPAN></H2>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 36pt; LINE-HEIGHT: 150%; mso-layout-grid-align: none; mso-char-indent-count: 3.0; mso-char-indent-size: 12.0pt"><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt"> <o:p></o:p></SPAN>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 150%; mso-layout-grid-align: none"><B><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">3 </SPAN></B><B><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">摩尔比法</SPAN></B><B><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt"><o:p></o:p></SPAN></B>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 24pt; LINE-HEIGHT: 150%; mso-layout-grid-align: none; mso-char-indent-count: 2.0; mso-char-indent-size: 12.0pt"><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">摩尔比法也称饱和法。此法是根据在配合反应中金属离子</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">M</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">被显色剂</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">R</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">所饱和的原理来测定配合物的组成的。</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt"><o:p></o:p></SPAN>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 24pt; LINE-HEIGHT: 150%; mso-layout-grid-align: none; mso-char-indent-count: 2.0; mso-char-indent-size: 12.0pt"><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">在实验条件下，我们制备一系列体积相同的溶液。在这些溶液中，固定金属离子</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">M</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">的浓度，依次从低到高地改变显色剂</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">R</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">的浓度，然后测定每份溶液的吸光度</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">A</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">，随着</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">[R]</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">的加大，形成配合物的浓度</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">[MR<SUB>n</SUB>]</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">也不断增加，吸光度</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">A</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">也不断增加，当</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">[R] </SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">：</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">[M]</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">＝</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">n</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">时，</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">[MR<SUB>n</SUB>]</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">最大，吸光度也应最大。这时</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">M</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">被</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">R</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">饱和，若</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">[R]</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">再增大，吸光度</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">A</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">即不再有明显增加。用测得的吸光度对</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">[R] / [M]</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">作图，所得曲线的转折点相对应的</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">[R] / [M]</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">值，即为配合物的组成比。</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt"><o:p></o:p></SPAN>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 24pt; LINE-HEIGHT: 150%; mso-layout-grid-align: none; mso-char-indent-count: 2.0; mso-char-indent-size: 12.0pt"><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">用摩尔比法可以求配合物</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">MR<SUB>n</SUB></SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">的稳定常数</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">K</SPAN><SUB><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">稳</SPAN></SUB><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">，其反应式为</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt"><o:p></o:p></SPAN>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 150%; TEXT-ALIGN: center; mso-layout-grid-align: none" align=center><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">M</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">＋</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">nR</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">＝</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">MR<SUB>n</SUB><o:p></o:p></SPAN>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 150%; TEXT-ALIGN: center; mso-layout-grid-align: none" align=center><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">K</SPAN><SUB><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">稳</SPAN></SUB><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">＝</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">[MR<SUB>n</SUB>] /</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">（</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">[M][R]<SUP>n</SUP></SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">）</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt"><o:p></o:p></SPAN>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 24pt; LINE-HEIGHT: 150%; mso-layout-grid-align: none; mso-char-indent-count: 2.0; mso-char-indent-size: 12.0pt"><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">当金属离子</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">M</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">有一半转化为配合物</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">MR<SUB>n</SUB></SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">时，即</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">[MR<SUB>n</SUB>]</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">＝</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">[M]</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">，则</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt"><o:p></o:p></SPAN>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 150%; TEXT-ALIGN: center; mso-layout-grid-align: none" align=center><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt"><SPAN style="mso-spacerun: yes"> </SPAN>K</SPAN><SUB><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">稳</SPAN></SUB><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">＝</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">1 / [R]<SUP>n</SUP><SPAN style="mso-spacerun: yes"> </SPAN></SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">（</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">1-33</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">）</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt"><o:p></o:p></SPAN>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 24pt; LINE-HEIGHT: 150%; mso-layout-grid-align: none; mso-char-indent-count: 2.0; mso-char-indent-size: 12.0pt"><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">因此，只要取摩尔比法曲线的最大吸光度的一半所对应的</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">[R]</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">，并将已求得的</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">n</SPAN><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">代入，即可求得配合物的稳定常数</SPAN><SPAN lang=EN-US style="FONT-SIZE: 12pt; mso-font-kerning: 0pt">K</SPAN><SUB><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">稳</SPAN></SUB><SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ^Times New Roman^; mso-font-kerning: 0pt; mso-hansi-font-family: ^Times New Roman^">。</SPAN>
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